A cross-sectional study of the association between circulating 25-hydroxyvitamin D levels and predicted operative mortality of patients with cardiovascular disease.

Recent studies have suggested that low levels of 25-hydroxyvitamin D (25OHD) are associated with cardiovascular risks in medical patients. However, these associations have not been well documented in high risk surgical patients. We hypothesized that serum 25OHD, 1,25-dihydroxyvitamin D (1,25OHD) would be associated with the cardiac operative risk stratification score. The study was conducted with a cross-sectional design at a single academic medical center in Japan. Two hundred five adult patients scheduled for major cardiovascular surgery were included consecutively. Cardiac operative risk was evaluated with the European System for Cardiac Operative Risk Evaluation (EuroSCORE) scoring system. Correlations between 25OHD and 1,25OHD, and EuroSCORE were assessed using simple and multiple linear regression models. Mean 25OHD and 1,25OHD were 20.1 ± 7.1 ng/mL and 51.2 ± 19.2 pg/mL, respectively. Half and 88% of the study population showed deficient (<20 ng/mL) and insufficient (<30 ng/mL) 25OHD levels, respectively. In contrast, only 3% showed 1,25OHD levels lower than normal (<20 pg/mL). Circulating 25OHD levels, but not 1,25OHD levels, were negatively correlated with EuroSCORE (p=0.005) even after adjusted for body mass index, albumin, hypertension, dyslipidemia, diabetes mellitus, creatinine, use of statin, high sensitive C-reactive protein, and intact parathyroid hormone. These results suggest that serum 25OHD levels are inversely associated with operative risk severity of patients undergoing major cardiovascular surgery.

Serum vitamin D levels and survival of patients with colorectal cancer: post-hoc analysis of a prospective cohort study.

BACKGROUND: Recently, serum 25-hydroxyvitamin D (25OHD) levels were shown to be associated with the survival of patients with colorectal cancer. However, 25OHD levels were measured a median of 6 years before diagnosis or were predicted levels. In this study, we directly measured serum 25OHD levels at surgery and examined the association with survival among patients with colorectal cancer. METHODS: We started a prospective cohort study to find prognostic factors in patients with colorectal cancer from 2003 to 2008 and stored serum samples and clinical data. As part of a post-hoc analysis, serum 25OHD levels were measured by radioimmunoassay. Association between overall survival and serum 25OHD levels were computed using the Cox proportional hazard model adjusted for month of serum sampling as well as age at diagnosis, gender, cancer stage, residual tumor after surgery, time period of surgery, location of tumor, adjuvant chemotherapy and number of lymph nodes with metastasis at surgery. Unadjusted and adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were determined. RESULTS: Serum 25OHD levels were measured in 257 patients. Only 3% had sufficient levels (30 ng/ml and greater). Based on month of blood sampling, an annual oscillation of 25OHD levels was seen, with levels being lower in spring and higher in late summer. Higher 25OHD levels were associated with better overall survival under multi-variate analysis (HR, 0.91: 95% CI, 0.84 to 0.99, P = 0.027). CONCLUSIONS: These results suggest that higher 25OHD levels at surgery may be associated with a better survival rate of patients with colorectal cancer.